Morphological and biochemical characterization of strains of Xanthomonas axonopodis pv. vignicola isolated from cowpea grown in three agroecological zones in Nigeria

Cowpea bacterial blight (Xanthomonas axonopodis pv vignicola) is a devastating disease of cowpea in Nigeria. Accurate identification is the first step for an effective management option. Thus, X. axonopodis pv. vignicola isolated from cowpea (Vigna unguinculata (L.) Walp) grown in different Agro-ecological zones in Nigeria were characterized using morphological characteristics, biochemical and antibiotic sensitivity tests. Pot experiments were conducted on two susceptible lines of cowpea (IT90k – 76) and (IT84s – 2246 – 4) in the screen house. In vivo infectivity studies were carried out to determine the effect of each of theX. axonopodis pv. vignicola isolate groups on the cowpea. All isolates from each of the agroecological zones were classified into Group 1 (light yellow) and Group 2 (brownish yellow) based on their morphological presentation on nutrient agar medium. Results from four of the biochemical test showed differences between the two morphologically different groups. Group 2 isolates showed a large zone of inhibition to a Lincomycin hydrochloride while isolates from Group 1 were not affected by the action of the same antibiotic. Blight symptom was only observed when the two types of isolates were combined and inoculated simultaneously. This study showed that there are two morpho-types of X. axonopodis pv. vignicola and their synergetic infectivity results in blight symptoms expression in cowpea

Review - Potential of probiotics as biotherapeutic agents targeting the innate immune system

Probiotics had been of interest in the promotion of good health in animals and man. Some of the positive effects of probiotics are: growth promotion of farm animals, protection of host from intestinal infections, alleviation of lactose intolerance, relief of constipation, anticarcinogenic effect, anticholesterolaemic effects, nutrient synthesis and bioavailability, prevention of genital and urinary tract infections, and immunostimulatory effects. Their beneficial effects may be mediated by direct antagonism of specific groups of organisms, resulting in a decrease in numbers or by an effect on their metabolism or by stimulation of immunity. The resistance of people in developing countries to diseases can be improved upon by promoting the consumption of locally fermented foods that are rich in probiotic organisms. This article reviews the potential of probiotics as immuno-enhancing agents and the future perspective in developing potent probiotics with immunostimulatory molecules that can serve as outstanding vaccine adjuvants

Short Communication - Phenotypic characterisation and assessment of the inhibitory potential of Lactobacillus isolates from different sources

Six strains of Lactobacillus   spp. were isolated from fermenting corn slurry, fresh cow milk, and the faeces of pig, albino rat, and human infant. Their inhibitory action was tested against some spoilage and pathogenic bacteria. Lactobacillus acidophilus   isolated from milk was found to display a higher antagonistic effect with zones of inhibition of 6 and 15 mm against E. coli and Pseudomonas aeruginosa   respectively. This isolate was incapable of inhibiting the other indicator bacteria. The other isolates have zones of inhibition ranging between 1 to 4 mm. Characterisation of the microbial metabolic product for antimicrobial agents reveals that lactic acid may be responsible for the inhibition of the indicator organisms

Short communication - Performance of rats orogastrically dosed with faecal strains of Lactobacillus acidophilus and challenged with Escherichia coli

Albino rats (Rattus norvegicus   ) were orogastrically dosed with faecal strains of Lactobacillus acidophilus   and simultaneously infected with Escherichia coli   , while the control was challenged with E. coli alone. The treatment was repeated the second day and post ingestion period of 18 days follow. It was observed that rats dosed with L. acidophilus and simultaneously challenged with E. coli treatments have better performances when compared with the control for daily weight gain, total weight gain and feed conversion rate. Faecal materials of rats dosed and challenged do not show sign of diarrhoea which was observed in the E. coli only treated rats